Identifies a specific release or version of a product. If you release a major new version of your software, the Product Code must change.
Its primary purpose is to act as the definitive identifier for your product. The Product Code is stored in the registry under the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall key, which is named after the Product Code GUID itself. This is why each product has a unique key, preventing conflicts that could arise if two installations shared the same product name. installshield product code
You release App v1.0 (Product Code A). Later, you build App v1.1 but . Your users install v1.1. What happens? Windows Installer sees Product Code A already installed, so it enters "maintenance mode" or fails with an error. Users end up with two separate entries in Control Panel – one that works and one that is broken. Identifies a specific release or version of a product
Navigate to the section in the left-hand View List. Click on General Information . Locate the Product Properties category in the central pane. The Product Code is stored in the registry
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
Identifies a general family of products across multiple versions. The Upgrade Code remains identical across version 1.0, version 2.0, and version 3.0. This allows the installer to find and remove older versions during a Major Upgrade.